1. Field of the Invention
The present invention relates to a driving method of a plasma display panel. More particularly, the present invention relates to a driving method of a plasma display panel that can improve discharge efficiency, extend panel lifetime, and reduce an operating temperature by detecting an average signal level and applying overlapping sustain pulses or non-overlapping sustain pulses depending upon the average signal level during a sustain period.
2. Description of the Related Art
A conventional plasma display panel includes address electrode lines, front and rear dielectric layers, scan electrode lines, sustain electrode lines, fluorescent layers, barrier ribs, and a magnesium monoxide (MgO) protective layer between a front substrate and a rear substrate.
The address electrode lines are formed in a predetermined pattern on the rear substrate. The rear dielectric layer is formed on the address electrode lines. The barrier ribs are formed on the rear dielectric layer in a direction parallel to the address electrode lines. The barrier ribs define a discharge space of each discharge cell and prevent optical interference between the discharge cells. The fluorescent layers are formed on the rear dielectric layer on the address electrode lines between the barrier ribs. The fluorescent layers include red fluorescent layers, green fluorescent layers, and blue fluorescent layers, which are sequentially disposed.
The sustain electrode lines and the scan electrode lines are formed in a predetermined pattern on the front substrate to intersect the address electrode lines. The respective intersections define the corresponding display cells. The respective sustain electrode lines and the respective scan electrode lines can have a transparent electrode line made of a transparent conductive material, e.g., ITO (Indium Tin Oxide), and a metal electrode, i.e., a bus electrode, line for enhancing conductivity. The front dielectric layer is formed to cover the sustain electrode lines and the scan electrode lines. The protective layer for protecting the panel from strong electric fields is formed on the whole front dielectric layer. A gas for forming plasma is enclosed in the discharge spaces.
In order to drive the conventional plasma display panel, one subfield includes a reset period, an address period and a sustain period, and driving signals are applied to the address electrode lines, the sustain electrode lines, and the scan electrode lines.
First, during the reset period, a reset pulse is applied to all of the scan electrode lines and reset discharge is performed, thereby initializing wall charges in all the discharge cells.
Next, during the address period, in order to select cells, scanning pulses are sequentially applied to the scan electrode lines and display data signals are applied to the address electrode lines of the cells to be selected.
Next, during the sustain period, in order to allow the cells selected during the address period to perform sustain discharge, sustain pulses are alternately applied to the sustain electrode lines and the scan electrode lines.
However, the sustain pulses having a sustain discharge voltage applied to the scan electrode lines and the sustain electrode lines during the sustain period do not temporally overlap. In other words, non-overlapping sustain pulses are applied thereto. As a result, the frequency of the sustain discharge successively occurring decreases, resulting in an increased sustain period or a decreased discharge efficiency.